git.sesse.net Git - casparcg/blob - common/concurrency/executor.h

   1 /*\r
   2 * copyright (c) 2010 Sveriges Television AB <info@casparcg.com>\r
   3 *\r
   4 *  This file is part of CasparCG.\r
   5 *\r
   6 *    CasparCG is free software: you can redistribute it and/or modify\r
   7 *    it under the terms of the GNU General Public License as published by\r
   8 *    the Free Software Foundation, either version 3 of the License, or\r
   9 *    (at your option) any later version.\r
  10 *\r
  11 *    CasparCG is distributed in the hope that it will be useful,\r
  12 *    but WITHOUT ANY WARRANTY; without even the implied warranty of\r
  13 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\r
  14 *    GNU General Public License for more details.\r
  15 \r
  16 *    You should have received a copy of the GNU General Public License\r
  17 *    along with CasparCG.  If not, see <http://www.gnu.org/licenses/>.\r
  18 *\r
  19 */\r
  20 #pragma once\r
  21 \r
  22 #include "../exception/win32_exception.h"\r
  23 #include "../utility/string.h"\r
  24 #include "../utility/move_on_copy.h"\r
  25 #include "../log/log.h"\r
  26 \r
  27 #include <tbb/atomic.h>\r
  28 #include <tbb/concurrent_queue.h>\r
  29 \r
  30 #include <boost/thread.hpp>\r
  31 #include <boost/optional.hpp>\r
  32 #include <boost/noncopyable.hpp>\r
  33 \r
  34 #include <functional>\r
  35 \r
  36 namespace caspar {\r
  37 \r
  38 namespace detail {\r
  39 \r
  40 typedef struct tagTHREADNAME_INFO\r
  41 {\r
  42         DWORD dwType; // must be 0x1000\r
  43         LPCSTR szName; // pointer to name (in user addr space)\r
  44         DWORD dwThreadID; // thread ID (-1=caller thread)\r
  45         DWORD dwFlags; // reserved for future use, must be zero\r
  46 } THREADNAME_INFO;\r
  47 \r
  48 inline void SetThreadName(DWORD dwThreadID, LPCSTR szThreadName)\r
  49 {\r
  50         THREADNAME_INFO info;\r
  51         {\r
  52                 info.dwType = 0x1000;\r
  53                 info.szName = szThreadName;\r
  54                 info.dwThreadID = dwThreadID;\r
  55                 info.dwFlags = 0;\r
  56         }\r
  57         __try\r
  58         {\r
  59                 RaiseException( 0x406D1388, 0, sizeof(info)/sizeof(DWORD), (DWORD*)&info );\r
  60         }\r
  61         __except (EXCEPTION_CONTINUE_EXECUTION){}       \r
  62 }\r
  63 \r
  64 }\r
  65 \r
  66 enum task_priority\r
  67 {\r
  68         high_priority,\r
  69         normal_priority,\r
  70         priority_count\r
  71 };\r
  72 \r
  73 enum thread_priority\r
  74 {\r
  75         high_priority_class,\r
  76         above_normal_priority_class,\r
  77         normal_priority_class,\r
  78         below_normal_priority_class\r
  79 };\r
  80 \r
  81 class executor : boost::noncopyable\r
  82 {\r
  83         const std::string name_;\r
  84         boost::thread thread_;\r
  85         tbb::atomic<bool> is_running_;\r
  86         \r
  87         typedef tbb::concurrent_bounded_queue<std::function<void()>> function_queue;\r
  88         function_queue execution_queue_[priority_count];\r
  89                 \r
  90         template<typename Func>\r
  91         auto create_task(Func&& func) -> boost::packaged_task<decltype(func())> // noexcept\r
  92         {       \r
  93                 typedef boost::packaged_task<decltype(func())> task_type;\r
  94                                 \r
  95                 auto task = task_type(std::forward<Func>(func));\r
  96                 \r
  97                 task.set_wait_callback(std::function<void(task_type&)>([=](task_type& my_task) // The std::function wrapper is required in order to add ::result_type to functor class.\r
  98                 {\r
  99                         try\r
 100                         {\r
 101                                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 102                                         my_task();\r
 103                         }\r
 104                         catch(boost::task_already_started&){}\r
 105                 }));\r
 106                                 \r
 107                 return std::move(task);\r
 108         }\r
 109 \r
 110 public:\r
 111                 \r
 112         explicit executor(const std::wstring& name) : name_(narrow(name)) // noexcept\r
 113         {\r
 114                 thread_ = boost::thread([this]{run();});\r
 115                 is_running_ = true;\r
 116         }\r
 117         \r
 118         virtual ~executor() // noexcept\r
 119         {\r
 120                 stop();\r
 121                 join();\r
 122         }\r
 123 \r
 124         void set_capacity(size_t capacity) // noexcept\r
 125         {\r
 126                 execution_queue_[normal_priority].set_capacity(capacity);\r
 127         }\r
 128 \r
 129         void set_priority_class(thread_priority p)\r
 130         {\r
 131                 begin_invoke([=]\r
 132                 {\r
 133                         if(p == high_priority_class)\r
 134                                 SetThreadPriority(GetCurrentThread(), HIGH_PRIORITY_CLASS);\r
 135                         if(p == above_normal_priority_class)\r
 136                                 SetThreadPriority(GetCurrentThread(), ABOVE_NORMAL_PRIORITY_CLASS);\r
 137                         else if(p == normal_priority_class)\r
 138                                 SetThreadPriority(GetCurrentThread(), NORMAL_PRIORITY_CLASS);\r
 139                         else if(p == below_normal_priority_class)\r
 140                                 SetThreadPriority(GetCurrentThread(), BELOW_NORMAL_PRIORITY_CLASS);\r
 141                 });\r
 142         }\r
 143                                 \r
 144         void stop() // noexcept\r
 145         {\r
 146                 is_running_ = false;    \r
 147                 execution_queue_[normal_priority].try_push([]{}); // Wake the execution thread.\r
 148         }\r
 149 \r
 150         void wait() // noexcept\r
 151         {\r
 152                 invoke([]{});\r
 153         }\r
 154 \r
 155         void join()\r
 156         {\r
 157                 if(boost::this_thread::get_id() != thread_.get_id())\r
 158                         thread_.join();\r
 159         }\r
 160                                 \r
 161         template<typename Func>\r
 162         auto begin_invoke(Func&& func, task_priority priority = normal_priority) -> boost::unique_future<decltype(func())> // noexcept\r
 163         {       \r
 164                 // Create a move on copy adaptor to avoid copying the functor into the queue, tbb::concurrent_queue does not support move semantics.\r
 165                 auto task_adaptor = make_move_on_copy(create_task(func));\r
 166 \r
 167                 auto future = task_adaptor.value.get_future();\r
 168 \r
 169                 execution_queue_[priority].push([=]\r
 170                 {\r
 171                         try{task_adaptor.value();}\r
 172                         catch(boost::task_already_started&){}\r
 173                         catch(...){CASPAR_LOG_CURRENT_EXCEPTION();}\r
 174                 });\r
 175 \r
 176                 if(priority != normal_priority)\r
 177                         execution_queue_[normal_priority].push(nullptr);\r
 178                                         \r
 179                 return std::move(future);               \r
 180         }\r
 181         \r
 182         template<typename Func>\r
 183         auto invoke(Func&& func, task_priority prioriy = normal_priority) -> decltype(func()) // noexcept\r
 184         {\r
 185                 if(boost::this_thread::get_id() == thread_.get_id())  // Avoids potential deadlock.\r
 186                         return func();\r
 187                 \r
 188                 return begin_invoke(std::forward<Func>(func), prioriy).get();\r
 189         }\r
 190         \r
 191         void yield() // noexcept\r
 192         {\r
 193                 if(boost::this_thread::get_id() != thread_.get_id())  // Only yield when calling from execution thread.\r
 194                         return;\r
 195 \r
 196                 std::function<void()> func;\r
 197                 while(execution_queue_[high_priority].try_pop(func))\r
 198                 {\r
 199                         if(func)\r
 200                                 func();\r
 201                 }       \r
 202         }\r
 203         \r
 204         function_queue::size_type capacity() const /*noexcept*/ { return execution_queue_[normal_priority].capacity();  }\r
 205         function_queue::size_type size() const /*noexcept*/ { return execution_queue_[normal_priority].size();  }\r
 206         bool empty() const /*noexcept*/ { return execution_queue_[normal_priority].empty();     }\r
 207         bool is_running() const /*noexcept*/ { return is_running_; }    \r
 208                 \r
 209 private:\r
 210         \r
 211         void execute() // noexcept\r
 212         {\r
 213                 std::function<void()> func;\r
 214                 execution_queue_[normal_priority].pop(func);    \r
 215 \r
 216                 yield();\r
 217 \r
 218                 if(func)\r
 219                         func();\r
 220         }\r
 221 \r
 222         void run() // noexcept\r
 223         {\r
 224                 win32_exception::install_handler();             \r
 225                 detail::SetThreadName(GetCurrentThreadId(), name_.c_str());\r
 226                 while(is_running_)\r
 227                 {\r
 228                         try\r
 229                         {\r
 230                                 execute();\r
 231                         }\r
 232                         catch(...)\r
 233                         {\r
 234                                 CASPAR_LOG_CURRENT_EXCEPTION();\r
 235                         }\r
 236                 }\r
 237         }       \r
 238 };\r
 239 \r
 240 }